1. Field of the Invention
The present invention relates to castable refractory for a slide gate plate which is used for a molten steel container, such as ladle, a tundish or the like, and has high resistance to corrosion and spalling and excellent structure stability before heated.
2. Description of Related Art
In a conventional a molten-metal accommodating vessel such a ladle, a tundish or the like, a slide gate device is disposed at a steel outlet port which is formed on the bottom portion of the molten-metal accommodating vessel, and castable refractory has been known as being used as plate refractory for the slide gate device. However, the castable refractory itself can hardly keep sufficient corrosion resistance and abrasion resistance to molten steel. Therefore, as disclosed in Japanese Laid-open Patent Application No. Sho-58-188559 or No. Sho-64-48661, brick which is excellent in corrosion resistance and abrasion resistance is used as a core member for the core portion of the vessel which is directly brought into contact with the molten steel and the castable refractory is used as an outer-periphery member for holding the brick.
As described above, the conventional castable refractory for a slide gate plate has been used to surround the core member which is directly brought into contact with the molten steel because it is inferior to brick in corrosion resistance, spalling resistance and abrasion resistance. Therefore, it has been hitherto difficult to use the castable refractory as a core member. However, if it is possible to use a slide gate plate formed of only castable refractory as a core member to be brought into contact with molten steel metal without using brick, it is apparent that the manufacturing cost could be lowered. Accordingly, it has been required to develop novel castable refractory which has high resistance to corrosion and spalling and high temperature strength (i.e., high resistance to abrasion).